Ukrainian fugitive President Viktor Yanukovych is asking Russia's protection from "extremists", according to a statement published by three Russian news agencies.

Yanukovych, who fled from Ukraine's capital Kiev last week, said he still considers himself to be the legitimate leader.

He is staying in a Kremlin sanatorium just outside Moscow, according to reports in Russia.

He has not been seen publicly since Saturday. While the West has recognised the new Ukrainian government, whose forces drove Yanukovych from the capital, Russia still considers him the legitimate president.

The RBK news organisation reports that Yanukovych is staying at the Barvikha sanatorium, which is run by the presidential administration's property department.

A spokesman for department said he had no information about the report.

RBK says the information came from one of Russia's wealthiest businessmen and was confirmed by a government official.